Manufacture of armor-piercing projectiles, shells, and other hollow bodies



R. A. HADFIELD AND A. G. McK. JACK. MANUFACTURE OF ARMOR PIERCING PROJECTILES, SHELLS, AND OTHER HOLLQOW BODIES. APPLICATION FILED MAY 24, 1920.

1 35 1 99 Patented Nov. 9, 1920..

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In mentors Patented Nov. 9, 1920.

2 SHEETS-SHEET 2.

Invent 0115 v Pokrf/U/zdfild AGJWWI Jwk 191170 may APPLICATION FILED MAY 24, L920.

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R. A. HADHELD AND A. G. McK. JACK.

MANUFACTURE OF ARMOR PIERGING PROJECTILES, SHELLS, AND OTHER HOLLOW BODIES.

' UNITED" STATES PATENT OFF-ICE.

ROBERT ABBQTT'HADFIELD, OF WESTMINSTER, AND ALEXANDER GEORGE MQKENZIE I JACK, 0F BRINCLIFFE,

SHEFFIELD, ENGLAND,

OTHER HOLLOW Application 'filed May 24,

I T 0 all whom it concern provements in or Relatin to the Manufacture of Armor-Piercing rojectiles, Shells, andother-Hollow Bodies, of which the following is a specification.

In the manufacture of armor piercing projectiles, shells, and other hollow bodies by what is known as the extrusion process, that is to say, by piercing a central longitudinal hole in a solid metal blank by means of a longitudinally movable punch while the blank is held in a heatedstatewithin a stationary die or container, the wall of the projectile, shell or other hollow body is formed by metal displaced by the punch and caused to flow through an annular space left between the punch and the die or container,

In this extrusion process the metal constituting the wall of the armor piercing projectile, shell or other-hollowbody (hereinafter referred to as a shell) is caused to flow longitudinally in an outward direction and is not subjected to any compressive action that will cause lateral or radial movement of the metal except at the pointed free end portion of the punch wherelateral outward displacement of the .metalto form the wall takes place. Consequently, the metal constituting the wall of the shell is not worked to the fullest extent, that is to say,

the particles thereof are not subjected to such a degree of pressure and are not caused to move relatively to one another to such an extent, as is necessary and desirable to enable the best physical characteristics, which it is possible to impart to the metal used, to

be developed, particularly when the metal is steel, for instance nickel chromium steel.

Now thepresent invention has for its ob ject to enable the metal constituting the wall of a shell producedby the extrusion process to be worked to a greater extent than heretofore, and in a simple, j uick, effective and economical manner, wit out drawing the shell through dies, so that the physical characteristics of the 9 metal constituting such r 7 wall shall be considerably improved as com- Speeification of Letters Patent.

Patented Nov. 9, 1920. 1920. Serial No. 383,922.

pared with those possessed by the metal of the wall of the shell after the completionof the usual extrusion process.

For this purpose, in'the manufacture of a shell according to the present invention, the wall thereof is subjected while supported externally but not internally and while at a suitable temperature, to endwise compression so as to cause the metalof which it 'is compressed to flow longitudinally backward toward the base of the shell and radially inward throughout the length of the wall or the greater portion thereof.

' According to one mode of making ashell according to the invention, the wall of the shell 15 produced by the extrusion process in the manner hereinbefore described but instead of making the wall of the shell of a thlckness such that when the interior of the shell has been machined, the wall will be of the required finished thickness, that is to say, instead of making the wall ofthe shell of a thickness of the completed forging at one pressing or extg sion it isme by the extruslon process of less thickness than that required in the completed forging. Such an extrusion process is herein called'the modified extrusion process to distinguish it from the ordinary extrusion processmeferred to. The wall of the shell thus produced is afterward made of greater thickness by subject-' thereof. In this way the metal comprising. the wall of the shell is worked in an eflectual and advantageousmanner for the purpose hereinbefore set forth.

1 In'carrying out this modeof making a shell the shell isproduced by piercing a solid metal blank by the extrusion process but with a thinner wall than required in the completed forging and the extruded wall, while at a suitable temperature and while held within a die or container, is subjected to I endwise compression, as by forcing a plunger against its outer free end while it is unsupported internally, so that the metal,

of the wall will be caused to flow both longitudinally backward and radially inward,

the length of the wall being correspondingly reducedk By thismeans the metal will be set up or caused to flow inwardly to substantially a similar extent throughout the whole length of the cavity in the shell, so that 1 the cavity. after compression of the wall,

will be of substantially the desired form, 4

forging.

In the accompanying illustrative drawings, Figure 1 shows partly in side elevation and partly in vertical section, and more or less diagrammatically, apparatus suitable for carrying the invention into practice.

Figs. 2, 3, 4 and 5 are similar views to.

Fig. 1 showing different stages in the process of manufacturing a shell.

Figs. 6 and 7 are similar views to Fig. 5 showing modifications. A

In carrying out the invention for the manufacture of say armor piercing projectiles or high explosive shells, a solid cast steel blank a, (Fig. 1) heated to a suitable forging temperature, is placed in a die or container b and after being forced therein by a plunger 0 to cause it to properly fit the containerb as usual, is; pierced longitudinally by a punch of, as shown in Fig. 2, operated hydraulically, so as to form a shell blank having an extruded wall e as heretofore. Instead however of using a punch 03 having a diameter only appreciably smaller than that of the desired finished cavity in the shell.

subsequently produced bv machining, the

. punch d is made of adiameter substantially larger than that of the desired finished cavity so as to form a thinner wall than is required in the completed forging. By this means, considerably more work is done upon the material than would otherwise be the case. After this modified extrusion proces is finished, the punch 03 is removed and the wall-e of the shell, while still at a high temperature and held within the container 6 is, as shown in Fig. 3, sub ted to the endwise pressure of a longitudinally movable hydraulically operated plunger f whereby it is shortened, the metal composing it flowing longitudinally backward. and radially inward, say from the position shown in dotted lines at g to the position shown approximately by the full lines it, thereby causing an additional advantageous working of the metal composing it and reducing the cavity" or core 2 in the shell to a diameter and form approximating to that ,of the required forged dimensions. The form of the cavity or core i may, if desired, or when necessary, and as shown in Fig. 4 be rectified to the exact forged form required, by means of a rectifying punch or former is of the correct dimensions that is forced into it after the compression stage above described is completed. Or, as shown in Fig. 5, the rectifying punch. may be replaced by a punch or former [a that is of the required finished forged dimensions of the cavity in the shell and is slidably supported within the hollow compression plunger f, so that when the plunger is lowered on to the wall of the extruded shell, the former 0 will enter the cavity of theshell and be centrally supported therein by the conical lower end thereof and the plunger will descend over itand compress the wall .of the shell closely around it. Or, instead of making the plunger f and former k separatelv, as in Fig. 5, they may, as shown in Fig. 6, be made in one piece, or as shown in Fig. 7, in separate pieces rigidly fixed together, the=former in this case coming to the bottom of the cavity and insuring the cavity being of the required finished forged dimensions when the plunger f has completed its downstroke.

The final form of the. cavity or core z is, in each case, produced by machining the inner surface of the wall. I

In this manner the wall of the shell is, in the first operation ('Fig. 1) given considerably greater work than is usuallythe case, and in the second operation (Fig. 2) the further working effects an additional improvement in the physical propertiesof the material composing the wall of the shell The extrusion andcompression or setting 'up processes described may be effected in quick succession without removal of the extruded shell from the container until the whole operation is finished. The extruded shell may however be removed from the container and reheated should this become necessary or desirable and afterward be replaced in the container or placed in another container and subjected to the compression or setting up process.

Although it is preferred to make the shell by extrusion with a wall of less thickness than that required in the completed forging before subjecting it tocom ression, to cause movement of the metal in a longitudinal backward direction and in an inward -direction as hereinbefore described, such the wall produced by the endwise compression, may be reduced to the required thickness by another punching operation or by machining.

The plungers 0 and f and punch-d may, as indicated in Fig. 1, becarried by a slide or cross-head j that is capable of being traversed horizontally in a guideway in the lower side of the head l of the ram m of a vertically arranged hydraulic cylinder n. Or they may each be otherwise arranged.

What we claim is 1. In the manufacture of a shell, subjecting the wall of the shell while supported externally but not ,internally and while at a suitable temperature, to endwise compression so as to cause the metal of which it is composed to flow longitudinally backward toward the base of the shell and radially inward throughout the greater portion of the length of the wall, substantially as described for the purpose set forth.

2. In the manufacture of a shell by the extrusion process, forming the wall of the shell by the extrusion process of less thickness than that required in the completed forging and afterward subjecting such wall, while supported externally but not internally and in a heated condition, to endwise compression toward the base of the shell so as to cause the metal of which it is composed to flow in the reverse longitudinal direction to that in which it flowed during the extrusion process and also to flow in an inward radial direction, substantially as described.

3. In the manufacture of a shell, subjecting the wall of the shell while supported externally but not internally and while at a suitable temperature to endwise compression so as to cause the metal of which it is composed to flow longitudinally backward toward the base of the shell and radially inward throughout the greater portion of the length of the wall, and rectifying the form of the cavity of the shell to insure that it shall correspond to the exact forged form and dimensions required.

4. In the manufacture of a shell, subjecting the wall of the shell while supported externally but not internally and while at a suitable temperature, to endwise compression so as to cause the metal of which it is composed to flow longitudinally backward toward the base of the shell and radially inward throughout the greater portion of the length of thewall, and causing the inner surface of the resulting cavity of the shell to assume the exact forged form and dimensions required by finally arresting the radial inward movement of the metal when such 7 sion so as to cause the metal of which it is composed to flow longitudinally backward toward the base of the shell and radially inward throughout the greater portion of the length of the wall, the metal flowing radially inward being finally forced around and against a former, thereby insuring that the cavity of the shell is of the exact forged form and dimensions required.

6. In the manufacture of a shell, subjecting the wall of the shell while supported externally but not internally and While at a suitable temperature, to endwise compression so as to cause the metal of which it is composed to flow longitudinally backward toward the base of the shell and radially in-- ROBERT ABBOTT HADFIELD. ALEXANDER GEORGE McKENZlE JACK. 

